We previously conducted a study of menstrual function in a group of 400 women during which we developed algorithms to determine ovulatory status, day of ovulation and menstrual cycle disturbances such as short luteal phase that can also be applied to the new sample. This previously collected sample (or the Asians therein) will serve as a baseline comparison group for the current sample. In addition, it will provide a source of data on the effects of lifestyle (such as smoking and alcohol consumption) and demographic (such as age and ethnicity) factors on menstrual function, allowing for more efficient examination of a small group of exposed women in the current study. In addition to serum organochlorine levels, questionnaire measures of exposure (e.g. species-specific fish consumption, occupational exposure and previous residence) will be examined in relation to ovarian function defined as continuous measures (e.g. cycle length, steroid conjugate levels) and dichotomous abnormalities (e.g. short luteal phase or anovulation). At this time all data collection is complete, hormones measured and analyses begun.